It's a bit more complex than you think .... need to know what exatly is in those ISO's ... if it's some type of install it will be much harder than if it is something else. I'm betting it's an install, not much else comes in ISO format.
Ok, I'll give you a solution that will work only if it is NOT an install: (do NOT do the following if it is an install, because it probably wont work)
1) Extract the ISO using an archiving program. (I use this one:
http://www.izarc.org/ )
2) Rebuild the iso using either
http://www.click-now.net/forums/index.php?...ype=post&id=100or
http://www.snapfiles.com/get/silentnightcd.html (this one can build and burn iso images)
The reason it probably won't work if it is an install is because when you put in the DVD it will probably run the install, but when it asks you to put in the second CD and you put it in again ... there's a good chance the install will mess up (the first CD may start again, or something strange)
Of course ... it might work depending on the way in which the program asks for disks. (If you try this with an install, be prepared to waste a DVD)